Press control mechanism



Feb. 4, 1941. w. ERNST t PRESS CONTROL MECHANISM 2 Sheets-Sheet 1Gttorncgs Original Filed May 20, 1931 mill Feb. 4, 1941. I w ERNST Re.21,708

- PRESS CONTROL MECHANISM Original Filed May 20, 1931 2 Sheets-Sheet 2(IRE PRESS III Reissued Feb. 4, 1941 Re, Q

21,10: mass cosmos MECHANISM Walter Ernst, Mount Gilead, Ohio, assignor,by

mesne assignments, to The Hydraulic Press Corporation, lnc., Wilmington,DeL, a corporation of Delaware Original No. 2,053,184, MM semen-bei- 1,:0. Serial No. 538.827, May 20, 1931. Application 101 reissue October22, 1930, Serial No. 101,041

3 Claims. (CI. 60-42) The invention generally relates .to hydraulicpresses, particularly those of the type wherein a pump supplies thefluid pressure employed to move the platen toward and from the work, and

varied to meet the demand of particular operain the manually controlledand power operated tions. In this disclosure the invention is illusmeansabove referred to of means rendering the trated in combination with oneacceptable form press thus equipped self corrective so that if the ofsuch pump, namely, the Hele-Shaw type dlsplaten should tend, during idlestanding or,other- 2o closed in United States Letters Patent, 1,250,170wise, to coast or creep past the point at which of December 18, 1917.Briefly stated, such pumps it was or should be automaticallystopped, thereinclude a plurality of radially arranged cylinders sultant linearmovement of the platen will act and pistons, the rate and direction ofdischarge through the novel control means or linkage reeifected bywhichdepend upon the eccentricity of ferred to to automatically bring about apump the pistons relative to a drive shaft and the reoutput tocounteract the creeping or coasting spectively associated cylinders. Thepistons are movement and return to or hold the platen at its usuallycarried by a shiftable ring or the like, desired stop position. which,by means of a cross head or other control Other objects will in part beobvious and in element, may be shifted to vary the eccentricity part bepointed out hereinafter.

of the pistons and to thereby effect control of the To the attainment ofthe aforesaid objects and 30 pump discharge. Various other kinds ofvariable ends, the invention still further resides in the dischargepumps are known in the art, and it is novel details of construction,combination and to be understood that the present inventionrearrangement of parts, all of which will be first lates to controlmechanism which is also adaptafully described in the following detaileddescrip- 5 ble for use in connection with pumps differing in tion, thenbe particularly pointed out in the apsome respects from the pumpreferred to above pended claims, reference being had to the accomandillustrated in this particular disclosure. panying drawings, in which:

In its more detailed nature the invention re- Figure l is a somewhatdiagrammatic side elesides in. the combination with a press, pump andvation of a press embodying a simple form of the pump circuit of thecharacter stated of a novel invention adapted for full manual control,the 40 control means which is manually actuated to press cylinder beingshown in section for purbring about the desired control movement of theposes of illustration. pump controlling devices and which consists in aFigure 2 is a front elevation of the press shown control rod rotatableand slidable in stationary in Figure l, the connection of the circuitpipes bearings and having thread connection with the with the cylinderand the control means con- 45 press platen or some other part movablelinearly necting link being shown in cross section. with the platen, agear held against linear move- Figure 3 is a somewhat diagrammatic sideelement and having spline connection on the rod, a vation and partsection illustrating a press emhand wheel and gear for impartingrotation to bodying acombined power actuated and manualthe gear and rod,a lever having connection with ly controlled means for effecting thedesired op- 50 the pump controlling devices, and means coneration andadjustments of the press pump. necting the lever and rod so thatmovement of Figure 4 is a detail view in longitudinal section the rod inone direction or the other will be imand on an enlarged scale of a pilotvalve cylinder parted to the pump controlling devices to effect linerand piston valve element.

the desired control of the pump and press. A practical embodiment of theinvention is primarily has for its object to provide a novel manuallyactuated control linkage by employ-' ment of which it is possible tovery accurately control the output of the pump and thereby enabl use ofthe press on jobs requiring great accuracy. 1

The novel control mechanism referred to may be used in combination withpresses employing various types of pumps, preferably those capable ofbeing reversed and of having their output Another object of theinvention is to provide in combination with a hydraulic press and thepump" and its controlling devices which effect operation thereof, poweractuated means for operating the pump controlling devices, and manu- 5ally actuated control means of the character stated for controlling thepower actuated means to cause the press platen to move in exactproportion to the control movement of .the hand wheel, stoppingautomatically and accurately under control of the linear movement of theplaten regulated by the particular control means adjustment.

The invention further resides in the provision illustrated in theaccompanying drawings as being connected to a pump A of the radial,reversible, variable discharge type. In order to make the operation ofthe pump and control mechanism more readily understood, the pump isillustrated as having hydraulic connection with a hydraulic press or thelike B, it however being understood that specific details of the pressand hydraulic circuit constitute no part of the present invention.

As shown, the pump A includes a casing I, a

shaft 2 which may be driven from any suitable source of power, andcombined intake and discharge pipes 3 and 4. The pipe 3 is connected tothe upper end of the cylinder 5 of the press B and the pipe 4 isconnected to the lower end' of the cylinder. When the pump lsdischargingthrough the pipe 3, the ram 6 of the press will be moved downwardly toperform a pressing or other like operation, the pump at this timereceiving its intake principally from the lower end or the presscylinder. When the pump is reversed so as to discharge in the oppositedirection, that is, through the pipe 4, fluid will be drawn from theupper end of the cylinder and delivered under pressure to the lower endthereof to return the ram to its upper position. A

I compensating valve I of the kind fully disclosed in the United Statespatent to Walter Ernst 1,653,350, dated December 20, 1927, is connectedacross the pipes 3 and 4 and has its central cham-' her 8 connected to atank 8 by means of a pipe II for compensating for the unequal effectivecross sectional area of the cylinder 5 aboveand below the piston ii in amanner well understood in the art.

The above described. parts will be recognized as conventional. I willnow proceed to describe the control mechanism forming the subject matterof my present invention, a simple embodiment of which is disclosed inFigures 1 and 2 of the drawings and designated as the manuallycontrolled and operated form, a second or manually controlled poweroperated form also being disclosed in Figure B of the drawings.

In the simple form of the invention disclosed in Figure 1, M designatesthe control rods which project at one side of the pump A and which areB. The other arm 16 of the bell crank lever is connected as at H to acontrol rod Hi.

The control rod I8 is rotatably and slidably supported in bearings [9carried by the press frame, and a bevel gear 20 is spline connected uponthe rod as at 2|. The gear 20 meshes with with a gear 22 carried by thecontrol shaft 23 so that rotation imparted to the shaft 23 will betransmitted through the gears 22 and 20 to the rod la. The control shaft23 is rotatably mounted in bearings 24 supported on the press frame andis equipped with a hand wheel 25 by which it may be conveniently rotatedby the operator of th press.

The control rod 18 is also provided with a threaded portion 26 whichpasses through a threaded bore formed in the boss 21 carried by acontrol arm 28, which is in turn rigidly secured as at 2! tothe pressram to'which the piston 5 is connected.

From the foregoing description it will be obvious that'ii' the handwheel 25 is turned clockwise it will result in rotation toward the leftand linear movement downwardly oi the control rod l8 relative to thelinearly movable press ram. This downward movement of the control rod llwill rock the bell crank 44-46 and force the pump control rods ll towardthe right. This movement of the pump control rods I I will bring about ia pump pressure output through the pipe line 4 causing the piston 6 tomove upwardly.

In travelling upwardly the piston ram carries the arm 28 and the rodwith it and when the ram has travelled the distance predetermined byinitial adjustment of the hand wheel '25 it will have acted throughconnections 28, ll, I6- l4, l3 and I2 to move the rods H to the left totheir initial neutral position thus automatically cutting oil the pumpoutput.

Obviously if the hand wheel is rotated in a counter-clockwise direction,movement in the reverse direction will be eilfected and pressuresupplied through the pipe line 3 into the top of the cylinder 5will'serve to force the piston downwardly. Thus by manipulation of thehand wheel 25 very accurate control of the movement of the press platenmay be efiected, making it possible to employ a press thus equipped injobs requiring great accuracy such as the straightening of cam shaftsand the like. Turning of the hand wheel acts to lift or lower theplaten. The lifting or lowering movement will continue as long as thehand wheel is being manipulated and the movement will be in exactproportion to the amount of rotation of the hand wheel. It will beobserved that in effecting control of the press the two linearly movableparts, namely, the press ram and the control rod 18 are given relativelinear movement for the purpose of controlling the degree of movement tobe imparted to the press ram at a given interval. When the press ram isto be moved downwardly by action offected has returned the control rodII to its initial position at rest or neutral position, it will havereset the pump to its neutral position and travel of the press ram willthus be automaticah ly stopped.

The equipment above described is also self corrective. If during theoperation or when inactive the press platen should tend to coast orcreep slightly beyond the predetermined stop position it will move thecontrol rod l8 past its neutral position to thereby bring about areversal of pump action and set up a small pump output in the reversedirection thus counteracting the creeping tendency.

In Figure 3 of the drawings I have disclosed the invention in a form inwhich the pump adjustment is manually controlled and power operated asdistinguished from the manually controlled and manually operated formdisclosed hereinbefore. In the disclosure of this modified form of theinvention thesame pump structure, press structure and manual controlmechanism is employed and since these parts are constructed and operatedin thesame manner as hereinbefore described the-same referencecharacters primed are applied to like The additional control rods 33 areconnected by a cross head 3|.

A bracket 32 is mounted in fixed relation to the pump casing and servesto support a hydraulic cylinder 33 in which is mounted a double actinghydraulic piston 34. The piston 34 is proelements 39, Hand to vary thedischarge of the pump, means are provided for applying fluid pressure toeither side of the piston. In the form shown, this pressure-applyingmeans includes a.

low pressure pump 31 arranged to receive fluid from the tank 9' throughthe medium of a suction pipe 33 and to discharge fluid under arelatively low pressure through a pipe 39 to a pilot valve generallydesignated 49 which controls the application of pressure on therespective sides of the piston 34 through pipes 4| and 42.

The pilotvalve 40 includes a liner or sleeve 43 mounted in a bore in thepump casing. This liner is provided with ports 44 communicating with anannular recess 45 in the casing and with ports 45 axially spaced fromthe ports 44 and.

communicating with an annular recess 41. The discharge pipe 39 leadingfrom the low pressure pump 31 communicates with the interior of thesleeve or liner 43 midway between the ports 44 and the ports 45. Mountedin the liner 43 is a piston valve 48 having spaced heads 49 and 50formed on a stem the center-to center distance between the heads 49 and59 being the same as the center-to-center distance between the ports 44and the ports 46. The heads 49 and 50 are slightly wider than theassociated openings 44 and 45, so that, when the piston valve is in itsFigure 3 position, the heads 49 and 50 will just cover the ports 44 and45 respectively.

The stem 5|- of the piston valve extends outwardly through suitablepacking for pivotal connection with the upper end of a floating lever 52as at 53. The floating lever 52 is pivotally connected at anintermediate point as at 54 to a link 55, in turn pivotally connected tothe cross head I! as at 55, and the lower end of the floating lever ispivoted as at 51. to a link 58 which is in turn pivoted, as at 59, to.the lower end of, the manually operated bell crank lever arm l4,

In operation, if the control devices 25'-|4 are moved in a direction tomove the piston valve 43 to the right from its Figure 3 position, lowpressure fluid from the pipe 39 will enter the liner between the heads49 and 50 and will flow out through the ports 43 and annular recess 41,since the head 50 has been moved to the right of the ports 49. The fluidwill flow from the recess 41 through the pipe 4| to the right of thepiston 34, and will move the latter to the left, fluid contained in thecylinder 33 to the left of the piston 34 being expelled through the pipe42, the annular recess 45, the ports 44, and internal passage ill formedin the piston valve 48, a chamber 31 in the casing at the inner end ofthe liner 43,- and an exhaust pipe 52 which leads back to the tank 9'.As the piston 34 is moved to the left in this manner, the cross head 3|and the rod 30 will be also moved to the left and will adjust the pump Ato effect discharge through the pipe 3' of the pump, Assumingthat themanually operated control devices have been adjusted to move the valve48 to a definite position to the right of the Figure 3 position,movement of the piston 34 and resultant movement of the cross heads 3|and IT at opposite sides of the pump will continue until the valve 48has been returned nearly to its Figure 3 position through the rocking oithe floating lever 52 about the pivot 51 resulting from movement of thecross head l2 imparted to the floating lever through the link 55. Assoon as the piston valve 43 has been moved to this position, furtherflow of liquid to the right hand end of the cylinder 33.wil1 be arrestedand the piston 34, the cross heads 3| and It" will be brought to rest.

Similarly, if the manually operable control devices are moved to bringthe piston valve 48 to piston 34 to the right, the movement of thepiston being transmitted through the cross heads 3| and I2 to the rods30 and II of the pump to effect discharge through the pipe 4' of thepump. When the predetermined movement of the cross head l2 to the righthas taken place, the piston valve 49 will be automatically returnednearly to its Figure 3 position so as to prevent further flow of lowpressure fluid to the cylinders 33, thereby bringing the pump crossheads I2 and 3| to rest. From the foregoing, it will be observed thatdifferent degrees of movement of the control hand wheel 25 and connectedcontrol devices and the piston valve 48 will effect correspondinglydifferent degrees of movement of thepump cross heads l2 and 3| so as toproduce the desired direction and rate of discharge from the pump.

When the piston valve 48 is in its Figure 3 position, wherein the ports44 and the ports 45 are covered by the heads 49 and 50 respectively,fluid cannot flow through the pipe 39. In order to relieve the pressurein the pipe 39 when the valve is in this position, a relief pipe 53,including a pressure operated relief valve 64 of any suitable form,-isconnected between the pipe 39 and the tank 9'.

In accordance with a further feature of the invention, means areprovided for limiting the maximum pressure of fluid discharged by thepump. For limiting the pressure of fluid discharged through the pipe 3',a piston 65 mounted in a cylinder 65 has a stem 51 extending throughpacking 68 for connection with the cross head l2 as at 69. The cylinder56 communicates at its left hand end, as viewed in Figure 3 with thepipe 3' of the pump by means of a pipe 10, so that the pressure in thecylinder 65 and to the -left of the piston 65 is always the same as thepressure in the pipe 3. Assuming that the piston valve 48 has been movedto the right, and that the piston 34, and the cross head 3|, have beenmoved to the left to a predetermined position in the manner describedabove, these parts will remain in such position until the pressure inthe pipe 3 builds up to a predetermined extent, at which time thispressure, acting through the pipe 10 and in the cylinder 56, will actupon the piston 55 to move the latter to the right, this movement beingtransmitted through the stem 51' and cross head I! to the rods ii and tothe floating rings of the pump, thus moving the floating rings to theright and reducing the discharge rate of the pump.

It is desirable that means be also provided for limiting the maximumdischarge pressure of the 15 pump when the cross heads l2 and 3| and thefloating rings of the pump have'been moved to the right so as todischarge through the pipe 4' in the manner already described. For thispurpose, the piston 34 is provided with a plunger 1| extending into abore 12 in the head of the cylinder 33, the end of the borecommunicating at all times with the pipe 4' through the medium of a pipe13. Thus, when the piston 34 and cross heads I! and 3| have been movedto the right in the manner described above so as to effect apredetermined rate of discharge through the pipe 4', pressure built upto a predetermined extent in the'pipe 13 and the bore 12 will act uponthe plunger II to move the latter and the piston 34 to the left. It willbe understood that the unit pressure acting upon the relatively smallarea of the plunger II is much greater than the unit pressure actingupon the relatively-large area of the left hand face of the piston 34,so that this latter pressure is overcome by the high pressure in thebore 12. This results in movement of the piston 34 and cross heads l2and 3| to the left, and the reducing of the rate of discharge throughthe pipe 4' so as to limit the discharge pressure.

As shown in Figure 4, the valve heads 49 and 50 are of the same widthsas the associated ports 44 and 46, i. e., the valve heads are fittedwith zero la'p. Therefore, as soon as the piston 34 tends to move to theleft, it immediately produces a corresponding movement of the crossheaditself and with it the links 52 and valve 48, and

opens port 44, permitting the oil to escape through pipe 42, port 44into pipe 39 and force it out through the relief valve 64, line 63.Although a very smallmovement of piston 34 must take place to move pilotvalve head 50 out of the way, this movement is taken care of by theelasticity of the oil in pipe line 42. As soon as an ever-so-slightmovement of piston 50 is produced, the oil can escape through port 44into line 39. The same is true on reversal on the downward stroke whenthe pressure gets into line 10 and behind piston 55. This tends to forcepiston 34 to the right, i

compressing the oil in line 4|; also moving valve head 30 to the rightand opening port 46 so that the oil can escape through line 39, forcingopen relief valve 64 and escaping into the tank.

In order that this form of the invention may be more readily understood,a complete operating cycle of the circuit shown in Figure 3 will now bedescribed.

Assuming that the parts are in the relative positions shown in Figure 3,the pump will be "on neutral, that is, no fluid will be deliveredthrough either of the pipes 3' and 4'. When it is desired to effect adownward movement of the ram 6', the control devices are actuated tomove the control rod l3 upwardly causing the bell crank lever arm M tomove to the left to an extent dependent upon the desired rate ofdischarge of the pump and the desired distance of travel of the pressplaten. This will move the piston valve 43 to the right to admit fluidfrom the pipe 39 to the pipe 4| and to the right hand end of thecylinder 33. The piston 34 will be thereby moved to the left, movementof the piston being transmitted to the pump rings through the cross head3| and rods 30. When the pump rings have been moved to the left thedesired distance to a position dependent upon the original degree ofmovement of the hand wheel 25', the piston valve 48 will be returned toits Figure 3 position as described above, and the pump rings will beunder pressure to the upper end of the cylinder 5',

the ram thereby being driven downwardly. Whenat which time dischargefrom the pump will cease and the ram will be brought to rest.

If, during its downward travel, and before the automatic completion ofits downward stroke as above outlined, the ram should meet withresistance in such a manner as to build up an undesir- I able excesspressure in the pipe line 3', when this excess pressure has reached apredetermined value the piston 65 will be acted upon to move the crosshead l2 toward the right, thus adjusting the pump rings and reducing thedischarge rate of the pump.

In order to return the ram 6 to its upper position, the hand wheel 25'will be rotated in the reverse direction and to the desired degree,thereby effecting a movement of the piston valve 48 to the left anddirecting fluid from the pipe 38 to the left hand end of the cylinder33, thereby moving piston 34, and the cross heads 3| and I2, to theright in the manner described, for the purpose of directing fluid underpressure through the Pipe line 4' into the lower der 5'. Should excesspressure he built up in the pipe line 4 as above-described, thispressure will be transmitted through the pipe 73 to the bore 12 and willact upon the plunger ll to reversely move the piston 34 and the crosshead 3| toward the left as far as is necessary to properly decrease therate of discharge through the pipe line 4' and thus limit the pressurein that line. When the pump rods 30 have been moved to the right thepredetermined distance determined by the degree to which the hand wheelhas been rotated, the pilot valve 48 will have been returned to itsneutral position illustrated in Figure 3 and the pump rings will beautomatically brought to rest. The pump will then deliver fluid underpressure to the lower end of the cylinder 5', the ram thereby beingdriven upwardly. When the ram, and consequently the rod ill have beenmoved upwardly to an extent dependent upon the amount of previousrotation of the hand wheel 25', the bell crank lever-I6, link 53,floating lever, 52 and pilot valve 40 will function to admit fluid tothe right of piston 34 to move the latter and the pump rings to the leftuntil in neutral position, at which time discharge from the pump willcease and the ram will be brought to rest.

It will be apparent that the control mechanism disclosed herein may beused in connection with various kinds of pumps other than the typeillustrated herein, and that various other changes portion of thecylinmay be made without departing from the scope of the invention asdefined in the claims.

From the foregoing description taken in connection with the accompanyingdrawings, it is thought that the novel details of construction,.

ber disposed in a neutral position when the pump is inactive and adaptedto be moved from its neutral position to render said pump active in thedesired degree for imparting movement to the platen, an arm movable withthe platen and including a threaded bore. a control rod slidably androtatably supported on the press frame at the rear of the press andhaving a threaded portion operable in the threaded bore, linkageconnecting said rod and said member to move in unison, a bevel gearspline-connected on the rod, and an operating shaft supported on thepress frame and having secured thereon a bevel. gear enmeshed with therod carried gear for imparting rotation therethrough' to the rod, saidshaft extending forwardly to a point in front of said platen, and a handwheel on the front end of said shaft.

2. The combination with a hydraulic press including a cylinder and acooperating ram therein, of means for operating the ram in bothdirections including a variable discharge pump for supplying fluid underpressure to said cylinder for driving said ram, said pump having ashiftable flow control element adapted to occupy a neutral position inwhich the pump runs light and does not discharge fluid and adapted to bemoved to a in which the pump will discharge fluid to said cylinder,progressive movement of said element from said discharge-effectingposition to said neutral position producing a gradual diminishing of thepump discharge to zero; and means for moving said flow control elementin such manner as to effect predetermined exact degrees progressivemovement of interconnecting discharge-effecting position of movement ofthe ram under delicate control and without undue loss of power due towire drawing comprising a rod having threaded connection with said ramand being movable with the latter, means operatively connecting the rodto the control element of said pump, and means for rotating said rod tovary its position relative to said ram.

3. The combination with a hydraulic press including a cylinder and acooperative ram therein, of means for operating the ram in bothdirections including a variable discharge pump for supplying fluid underpressure to said cylinder for driving said ram, said pump having ashiftable flow control element adapted to occupy a neutral position inwhich the pump runs light and does not discharge fluid and adapted to bemoved to a discharge-effecting positicn in which the pump will dischargefluid to said cylinder, said element from said discharge-effectingposition to said neutral position producing a gradual diminishing oi thepump discharge to zero, mechanism operatively said ram with said flowcontrol element, said mechanism being continually movable during themotion of said ram and responsive to the travel of said mm for graduallyshifting said flow control element in a flow 1:- ducing direction, and ascrew actuated fine adjustment device associated with said mechanism andinterposed between said ram and said flow control element ior varyingthe relative position of said flow control element relatively to saidramby finely graduated increments.

- WALTER ERNST.

